Papermaking machine stock inlet



Dec. 26, 1967 J. LOYND 3,360,428

vPAPERMAKING MACHINE STOCK INLET Fil ed March 5, 1965 2 SheetsSheet 1 III/IIII/I/Il III/11111.

a; v v 51a- 51 Q 9 Dec. 26, 1967 LOYND 3,360,428

PAPERMAKING 'MACHINHSTOCK INLET aw y United States Patent 3,360,428 PAPERMAKING MACHINE STOCK INLET James Loynd, Neenah, Wis., assignor to Kimberly- Clarlr Corporation, Neenah, Wis., a corporation of Delaware Filed Mar. 5, 1965, Ser. No. 437,540 4 Claims. (Cl. 162-347) My invention relates to papermaking machines and more particularly to paper stock inlets for discharging paper stock onto a foraminous draining fabric or wire in a papermaking machine.

It has previously been proposed, in the copending patent application of David W. Appel et al., Ser. No. 278,521, filed May 2,1963, now abandoned, to provide a paper stock inlet comprising a pair of parallel plates forming a thin slot between them through which paper stock is directed onto a foraminous forming fabric or wire. The plates advantageously impart a fine scale turbulence between them for thoroughly dispersing the fibers in the stock slurry. The web width, and thus the width of the inlet, may be 120 inches or more; and the slot may be inch to inch in thickness. A serious problem is encountered if the thickness of the slot transversely of the machine is not maintained uniform, since non-uniformity will produce variations in basis weight of the paper web in the cross machine direction. The paper stock is discharged under considerable pressure, oftentimes in excess of 100 pounds per square inch; and this pressure tends to deflect the parallel plates. Nozzles of this type have in the past been built, using spacers between and connecting the parallel plates at their side edges; and this construction restricts or prevents the sides of the nozzle plates (generally coincident with the sides of the forming fabric) from deflecting under the influence of stock pressure; however, since the parallel plates tend to deflect, the nozzle opening and the spacing between the plates thus become greater in the center of the machine, permitting a greater volume of stock slurry to flow from the nozzle at the mid-section and resulting in the basis weight of the paper web being heavier in the mid-section than at the edges. In order that uniform width of the slot may be maintained in the cross machine direction, obviously the deflections of the two plates should be maintained the same under the action of this pressure.

It is an object of the present invention to provide an improved mode of construction of a stock inlet of this type having opposite parallel plates forming a thin slot through which slurry discharges, in which this differential deflection and consequent basis weight variation across the width of the machine is reduced or eliminated, so as to produce a web of paper which is substantially uniform in basis weight across the machine.

In brief, I accomplish this object by providing bars on the sides of the slot which are secured to only one of the parallel plates. A recessed slot is cut into each of the bars receiving a rectangular strip of composition material, such as Teflon or hard rubber, which seals the adjacent side edges of the two plates with respect to each other to prevent efiiux of the paper stock slurry sidewardly out of the slot and which allows one plate to move with respect to the other plate. Adjusting screws may be provided in the construction to apply the minimum pressure on these strips of composition material necessary to seal the slot at the sides of the parallel plates. There thus is only a slight frictional force of the composition seals against the side edges of the parallel plates to resist the deflection of the plates, and the plates are thus allowed to deflect uniformly across the width of the ma chine to maintain the basis weight of the sheet substantially uniform transversely of the machine.

The invention consists of the novel constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above stated objects, and such other objects, as will be apparent from the following description of a preferred form of the invention, illustrated with reference to the accompanying drawings, wherein:

FIG. 1 is a plan View of a papermaking machine stock inlet embodying the principles of the invention;

FIG. 2 is a side View of the inlet;

FIG. 3 is a sectional view on an enlarged scale taken on line 3-3 of FIG. 1;

FIG. 4 is a fragmentary sectional view similar to FIG. 3 but on a still further enlarged scale;

. FIG. 5 is a side view of the stock inlet;

FIG. 6 is a fragmentary end view of the inlet; and

FIG. 7 is a fragmentary elevational view of a papermaking machine having my improved inlet incorporated therein.

Like characters of reference designate like parts in the several views.

Referring now to the drawings and in particular to FIG. 7, the illustrated papermaking machine may be seen to comprise a Fourdrinier forming fabric or wire 10 which is disposed in the form of a loop about a plurality of supporting rolls, including rolls 11, 12 and 13. It will be noticed that the rolls 11, 12 and 13 are disposed generally one above the other, and there is a small gap between the rolls 11 and 12 and between the rolls 12 and 13. The wire 10 bridges each of these gaps, since the wire extends about the lefthand sides of the rolls 11 and 13 and about the righthand side of the roll 12 as these rolls are illustrated in FIG. 7. An endless felt 14 is supported in the form of a loop by means of a plurality of supporting rolls including the roll 12. The felt 14 partially wraps the roll 12 and is located between the roll 12 and the wire 10.

A paper stock inlet 15 embodying the principles of the invention is provided for directing paper stock into the gap between the rolls 11 and 12 and on to the portion of the wire 10 bridging the rolls 11 and 12. A paper web is formed on the Wire 10 and is disposed between the wire 10 and the felt 14 in the portions of the wire and felt wrapping the roll 12. Dewatering of the web occurs principally due to the pressure with which the wire 10 bears on the felt 14 and roll 12; and the paper web, as partially dewatered, follows the felt 1-4 from the roll 12. The wire 10 separates from the felt 14 and the web carried by the felt on a bottom portion of the roll 12 and moves to its other supporting rolls. Details of the papermaking machine generally described above are not considered necessary for the purposes of the present disclosure, and additional details may be obtained-from a copending application of Charles A. Lee and Charles A.

Lamb, Ser. No. 161,058, filed Dec. 21, 1961', and my copending application, Ser. No. 433,934, filed Feb. 19, 1965.-

Referring to FIGS. 1 and 2, the inlet 15 may be seen to comprise a stock supply conduit 16 connected, 'by means of a pair of intermediate stock conducting portions 17 and 18, with a terminal portion 19. Any suitable passages -(not shown) may be provided in the intermediate portion 17 connected with the interior of the stock supply conduit 16, and these passages are connected with a tapering passage 20 (see FIG. 3) provided in the intermediate portion 18. The passage 20 is connected to a thin slot 21 p which is provided in the terminal portion 19 of the inlet.

The slot 21 is defined principally by plates 22, 23, 24 and 25, and a pair of relatively short connecting plates '26 and 27 are provided between the plates 22 and 23 and the plates 24 and 25. The plates 22 and 24 are disposed in an upper rigid casingpart 28, and the plates 23 and 25 are disposed in a lower rigid casing part 29. The casing parts 28 and 29 are fixed by means of a plurality of cap screws 30 and 31 on to a fiat face 32 of the intermediate inlet portion 18.

An end seal bar 33 (see FIG. is fixed on each side of the inlet (only one side and one bar 33 being illustrated) with respect to the intermediate inlet portion 18 by means of a plurality of cap screws 34 and 35; and a gasket 36 of rubber-like material is provided between the bar 33 and the fiat face 32. An end seal mount 37 is fixed on each side of the inlet 15 with respect to the lower casing part 29 by means of a plurality of screws 38. Each end seal mount 37 is provided with a longitudinal groove 37a therein (see FIG. 6), and a bar 39 is disposed within the groove 37a. The bar 39 has a longitudinal slot 39a formed in it which is closed by a lug 39b, and an end seal strip 40 of composition material is disposed within the slot 39a. The strip 40 rests on the lug 39b, and, as will be noted, it is slightly greater in thickness than the depth of the slot 39a.

Each end seal mount 37 is provided with a plurality of screws 41 extending therethrough, and these screws bear on the associated bar 39 along a longitudinal line thereof. A strip 40, which protrudes slightly from the slot 39a in the bar 39, thus is forced against the adjacent edges of the plates 22 to 27 for sealing the sides of the slot 21. A screw 41a extends through each end seal bar 33 and augments the action of the screws 41 in pressing the strip 40 against the edges of the plates 22 and 23. Each strip 40 is slightly longer than the slot 39a in which it is disposed, and the strip 40 makes contact with and slightly depresses the surface of the associated end seal gasket 36, so that the end of the strip 40 makes a seal with respect to the gasket 36.

A lug 42 is fixed on each bar 39, and a screw 43 extends through the lug 42. The lug 42 and screw 43 are disposed in a slot 37b provided in the associated end seal mount 37, and the screw bears on the outer edge of the slot 37b to hold the strip 40 in forceful contact with the gasket 36. The bars 39 and the seal strips 40 may be adjusted longitudinally by means of the screws 43 to tighten the seals of the strips 40 on the gaskets 36.

The plates 22 and 23, as will be noted from FIG. 3, are slightly thicker than are the plates 24 and 25 which protrude from the inlet 15; and the plates 24 and 25 are relatively flexible. The plates 22 and 23 are fixed by any suitable means, such as the screws 44, with respect to adjacent parts of the inlet. The plates 24 and 25 are respectively fixed with respect to the connecting plates 26 and 27, as by rivets 45 (see FIG. 4). The plates 26 and 27 are disposed within slots 46 and 47 extending transversely of the inlet; and, as will be noted, the slots 46 and 47 are wider than are the connecting plates 26 and 27 and have obliquely extending ends 46a and 47a. The plates 26 and 27 have acute angled side edges, and these fit within the correspondingly shaped ends 46a and 47a of the slots 46 and 47, as is apparent from FIG. 3. The plates 26 and 27 also have acute angled side edges 26a and 27a, and the plates 26 and 27 are held in their illustrated positions bearing against the sides 46a and 47a of the slots 46 and 47 by means of tension pins 48 extending through the upper and lower casing parts 28 and 29. Each of the tension pins 48 is provided with a lug portion 48a on its end which embraces the side edge 26a or 27a of a plate 26 or 27.

The upper and lower casing parts 28 and 29 are provided with notches 49 and 50 at their ends, and channel shaped members 51 and 52 fit within these notches and are respectively fixed with respect to the plates 24 and 25. Adjustment screws 53 are disposed within the upper and lower casing parts 28 and 29 and extend through openings 51a and 52a provided in the members 51 and 52 and bear on the plates 24 and 25. The screws 53 are each provided with an adjusting nut assembly 54 on its end, so that the screws may be moved toward or away from the slot 21 4 to adjustably move the plates 24 and 25 and vary the thickness of the slot 21.

The strips 40 are each made of a composition material which is somewhat yieldable and provides little friction on the edges of the plates 24 and 25, so that one of the plates may move with respect to the other at their edges. In particular, the static coefficient of friction of the material should be low when the material is wet. Due to the yieldability of the composition, the strips 40 perform well in sealing but they do not in any substantial way frictionally tie together the side edges of the parallel plates 24 and 25. The strips 40 may, for example, be made of Teflon, Delrin (an acetyl resin made by E. I. du Pont de Nemours & Co., Inc., of Buffalo, N.Y., U.S.A.); Rulon (Teflon that has been filled with a filler material to strengthen it structurally, made by Dixon Corporation of Bristol, R.I., U.S.A.); Micarta (a phenolic resin reinforced with fabric, made by Westinghouse Electric Corp. of Pittsburgh, Pa., U.S.A); Fiberglas reinforced Teflon or Fiberglas reinforced polyesters; hard rubber or oil-treated lignum vitae wood. Also, a material known as Eelslip, having these characteristics, is considered very useful, this being made by Johns-Manville of New York city, USA.

In operation, paper stock slurry under substantial pressure, such as, for example, pounds per square inch or more, is supplied from the conduit 16 through the intermediate portions 17 and 18 and the passage 20, to the slot 21 formed by the parallel plates 22 to 27. This paper stock slurry flows through the slot 21 and from its terminal end onto the wire 10, and a paper web is formed between the wire 10 and felt 14 about the roll 12, dewatering of the paper stock occurring principally due to the force with which the wire 10 bears on the felt 14 and roll 12. The wire 10 separates from the felt 14 below the roll 12 and the paper web follows the felt 14, due to the fact that the felt 14 is more dense than the wire 10.

The stock slurry under pressure tends to force the plates 24 and 25 apart. The plates 24 and 25 are initially adjusted to have a certain spacing between them by means of the adjusting screws 53. The pressure of the stock, however, does deflect the plates 24 and 25 in operation, tending to bow the plates outwardly, and the seal strips 40 allow the ends of the plates 24 and 25 to deflect in the same manner as the plates do at their centers, so that the slot 21 defined by the plates 24 and 25 remain uniform in thickness across the width of the machine. It will be noted that the strips 40 are fixed through the parts 37, 38 and 39 only with respect to the lower plate 25 and that the upper plate freely floats or moves on the seal strips 40 under the influence of the stock slurry under pressure.

The screws 41 bearing on the bars 39 carrying the strips 40 may be utilized for moving the strips 40 into contact with the edges of the plates 24 and 25 with just the right pressure so that the plates 24 and 25 are sealed with respect to each other but yet the plate 24 may move due to the pressure of the stock with little frictional resistance with respect to the strips 40 and plate 25. Thus, the plates 24 and 25 deflect uniformly across the width of the machine under the influence of stock pressure.

The sliding connection of the seal strips 40 on the edges of the plate 24 permits an adjustment in spacing of the plates 24 and 25 with a uniform gap between them for the full width of the inlet when no stock is being supplied to the inlet, and the gap between the plates 24 and 25 will be uniform across the inlet when the inlet subsequently is in use with stock under pressure being supplied to it. If the side edges of the parallel plates 24 and 25 were fixed together, these side edges could not yield along with the center portions of the plates under the influence of the stock under pressure, and the width of the gap between the parallel plates would thus change. The provision of the floating seals 40 at the side edges of the plates 24 and 25 allows the plates 24 and 25 to deflect in the same manner so that the. gap between them is uniform, when stock is passing through the inlet, even though the gap between the plates may be different in size and shape from the gap that existed when the machine was inoperative.

It will be observed that the seal strips 40 are held by means of the lugs 3912 against the rubber-like gaskets 36, and thus leakage between the ends of the strips 40 and the gaskets 36 does not occur. The screws 43 may be adjusted in order to move the bars 39 and strips 40 longitudinally to provide this seal.

I wish it to be understood that the invention is not to be limited to the specific constructions, arrangements and devices shown and described, except only in-so far as the claims may be so limited, as it will be understood to those skilled in the art that changes may be made without departing from the principles of the invention.

What is claimed is:

1. In a paper stock inlet for a papermaking machine the combination of a pair of relatively flexible substantially parallel plates providing a slot between them through which paper stock may discharge, and a seal strip on each side of the inlet in contact with the side edges of the plates for sealing the sides of the slot and allowing the side edges of the plates to move with respect to each other.

2. In a paper stock inlet for a papermaking machine, the combination of a pair of relatively flexible substantially parallel plates providing a slot between them through which paper stock may discharge, a relatively rigid inlet part on which each of said plates is carried, a seal strip on each side of the inlet in contact with the side edges of the plates for sealing the sides of the slot, and means for fixing each seal strip with respect to a first one of said rigid parts but not the second one of said rigid parts so as to allow the side edge of the plate carried by said second part to move with respect to the side edge of the plate carried by said first part.

3. In a paper stock inlet for a paperm-aking machine, the combination of a pair of relatively flexible substantially parallel plates between which paper stock may discharge, a rigid part carrying each of said plates, a mounting plate fixed with respect to one of said parts on each side of the inlet, a bar provided with longitudinal slots and carried by each of said mounting plates, and a strip of relatively yieldable sealing material located in each of said slots and making a seal with respect to the adjacent edges of said plates on each side of the inlet and allowing the side edge of one of the plates on each side of the inlet to move with respect to the side edge of the other plate.

4. In a stock inlet for a papermaking machine, the combination of a pair of relatively flexible substantially parallel plates providing a stock conveying slot between them from which stock may discharge, a rigid part carrying each of said plates, a mounting plate fixed with respect to one of said parts on each side of said inlet, a longitudinally slotted bar carried by each of said mounting plates, a seal strip of yieldable material disposed in the slot of each of said bars and in contact with adjacent side edges of said plates for sealing the sides of the stock conveying slot and allowing the side edge of one of the flexible plates to move with respect to the other flexible plate, adjusting screws extending through each of said mounting plates for moving the associated slotted bar toward side edges of the flexible plates for completing the seal of the stock conveying slot by the associated seal strip, a gasket of yieldable material for mounting said two rigid parts with respect to an adjacent inlet part, a lug on the end of each of the slots of said bars and located at the terminal end of said stock conveying slot for holding the associated seal strip in sealing contact with said gasket, and an adjustment device for longi tudinally moving each of said bars with respect to the associated mounting plate so as to change the sealing force of the associated seal strip with said gasket.

References Cited UNITED STATES PATENTS 3,215,593 11/1965 Green 162-336 X HOWARD R. CAINE, Primary Examiner. A. C, HODGSON, Assistant Examiner, 

2. IN A PAPER STOCK INLET FOR A PAPERMAKING MACHINE, THE COMBINATION OF A PAIR OF RELATIVELY FLEXIBLE SUBSTANTIALLY PARALLEL PLATES PROVIDING A SLOT BETWEEN THEM THROUGH WHICH PAPER STOCK MAY DISCHARGE, A RELATIVELY RIGID INLET PART ON WHICH EACH OF SAID PLATES IS CARRIED, A SEAL STRIP ON EACH SIDE OF THE INLET IN CONTACT WITH THE SIDE EDGES OF THE PLATES FOR SEALING THE SIDES OF THE SLOT, AND MEANS FOR FIXING EACH SEAL STRIP WITH RESPECT TO A FIRST ONE OF SAID RIGID PARTS BUT NOT THE SECOND ONE OF SAID RIGID PARTS SO AS TO ALLOW THE SIDE EDGE OF THE PLATE CARRIED BY SAID SECOND PART TO MOVE WITH RESPECT TO THE SIDE EDGE OF THE PLATE CARRIED BY SAID FIRST PART. 